PATHOLOGY.—The endocardium, although a serous membrane, is mixed with fibrous elastic tissue at its valvular reduplications, which accounts for the disease being so frequently associated with rheumatism, and for the morbid appearances more commonly witnessed in the valvular structure of the heart than elsewhere. The natural result of inflammation in this, as in other serous membranes, is the effusion of lymph, and consequent thickening, which sometimes interferes with the play of the valves, or narrows the auriculo-ventricular openings, thus producing the bellows-sound which has been described as one of the chief symptoms. The inflammation may extend to the muscular substance of the heart, which becomes darkened in color and easily broken down; while in some cases large quantities of fibrin are thrown out, which quite block up the auriculo-ventricular openings and orifices of the large blood-vessels. To Endocarditis may also be traced Tumors and Polypi, as well as Hypertrophy and Dilatation. Abscess in the walls of the heart has also been observed as a consequence of Endocarditis. DIAGNOSIS.—The pathognomic symptoms of Endocarditis are frequently very obscure, being like those of Pericarditis; but it is of very little consequence, as the treatment must be similar. However, the bellows-sound in the former, and the friction sound in the latter, are sufficient in the majority of cases to point out the nature of the disease when taken in connection with other symptoms which have been mentioned. PROGNOSIS.—Owing to the various terminations of Endocarditis, nearly all of a serious character, our opinion as to the ultimate result must be unfavorable, although in the majority of cases the animal appears to recover; but he is found afterwards not as good in his wind as formerly, easily distressed, and when going at an ordinary pace with hounds, will probably fall down and expire suddenly. A.A. will be our best resource. Hypertrophy—Enlargement of the Heart DEFINITION.—An abnormal growth of the muscular tissue of the heart by thickening of the walls. VARIETIES.—There are three. Simple Hypertrophy is the thickening of the walls without any change in the capacity of the cavities. Eccentric Hypertrophy is the thickening of the walls with dilatation of the cavities. Concentric Hypertrophy is the thickening of the walls with diminution of the cavities. The lesion is usually associated with other diseases, and especially with affections of the lungs. The disorder is slow in its progress, though it soon interferes with the working capacity of the animal. It predisposes to other lesions, such as congestion of the lungs, hemorrhage, etc.